1. Field of the Invention
The present invention relates to an improvement in a sensor for detecting the angular velocity and the acceleration which are applied to an apparatus.
2. Description of Related Art
Japanese Laid-Open Patent Application No. Hei 7-92175 has previously disclosed one type of gyrosensor for detecting angular velocities about two axes, which is suitable for use in an image-shake correcting system. The disclosed gyrosensor is an angular velocity sensor for detecting angular velocities about two axes by detecting whether the oscillation locus of an oscillator (or a plurality of oscillators), which is supported at one end (fixed at one end), is inclined by a Coriolis force, which is produced when an angular velocity is applied to the sensor while the oscillator is making a swivel motion.
However, since such angular velocity sensor has a structure in which the oscillator is provided with piezoelectric elements or one end of the oscillator having elasticity is fixed to a fixing member, the extent of miniaturization of the angular velocity sensor is limited. In addition, since the angular velocity sensor also has a structure in which two oscillators are fixed to the opposite sides of a common base and are made to swivel in the same direction, bulk micromachining is needed in the production of the angular velocity sensor by micromachining, so that time-consuming etching is needed and it is difficult in terms of cost to provide the aforesaid angular velocity signal as an angular velocity sensor for domestic use.
In addition, Japanese Laid-Open Patent Application No. Hei 7-92175 does not at all disclose a system for detecting an acceleration applied to the angular velocity sensor.
In addition, research in virtual reality has recently advanced and an announcement has been made of, for example, an application which detects the motion of a person through an angular velocity sensor and an acceleration sensor and visually displays an image corresponding to the motion detected. As a sensor for use with such application, it has been desired to develop a sensor capable of detecting not only angular velocities about two axes and accelerations in the directions of two axes, but also an angular velocity about, and an acceleration in the direction of, an axis extending in a direction perpendicular to the aforesaid mutually perpendicular two axes (an axis parallel to the longitudinal direction of the oscillator).
An object of the present invention is to provide a sensor which can detect an angular velocity signal and/or an acceleration with high accuracy in spite of its reduced size and cost.
To achieve the above object, in accordance with one aspect of the present invention, there is provided a sensor which comprises a plurality of weight portions which swivel, support parts each of which supports at one end a corresponding one of the plurality of weight portions in the same direction, and a driving part which supplies driving power to the support parts to swivel the plurality of weight portions, the driving part swiveling at least one weight portion of the plurality of weight portions in a first direction and a remaining weight portion in a second direction opposite to the first direction so that an angular velocity about an axis parallel to a predetermined swivel locus of the at least one weight portion, excluding an acceleration component in the direction of the axis, can be detected from the difference between a deviation of a swivel locus of the at least one weight portion from the predetermined swivel locus and a deviation of a swivel locus of the remaining weight portion from a predetermined swivel locus thereof.
Other aspects of the present invention will become apparent from the following detailed description of preferred embodiments of the present invention, taken in conjunction with the accompanying drawings.